Kumarans Data Academy

We use the NumPy library in data science with Python because it makes working with numbers and large datasets much faster and easier. Why NumPy is important in data science: NumPy stores data as arrays that uses less memory Applies Math Operations directly on all values in the array at once. We can work with 1D (vectors), 2D (matrices), and even higher-dimensional data. Libraries like Pandas , Scikit-learn , TensorFlow , and Matplotlib depend on NumPy for handling numeric data. NumPy has built-in functions for matrix multiplication, eigenvalues, random number generation, and statistical calculations.

When we use Python for data analysis, machine learning, or any programming, we do not write each and every code. Why Should we? Some experts already wrote code for us and packed it as a Library. This reusable collection of code is called a Python Library . A library in Python is like a ready-made toolbox. Instead of building every tool yourself, you take the tools from the toolbox and start using it in your code. Why do we need Python Libraries? Save time – We do not write the same code again and again. Easy to use – Just install, import, and start using. Powerful features – Some libraries can do complex tasks in one line of code. Community support – Big communities maintain them, so they keep improving. Examples of Python Data Science Libraries: Pandas – Works with data tables like Excel, filtering and summarizing data NumPy – Works with numbers, arrays, mathematical calculations Matplotlib – Creates graphs and charts Scikit-learn – For machine learning models like regres...

Mean: Its nothing but Average.  Well, what is Average? When you see some scoring Not Higher, Not Lower, but medium marks like 50, 60 etc.. we call them average student. Example : Now, I have 5 Students Marks: 10,40,51,68,98 What is the Average mark of this 5 Students? 53.4 is the Average score of 5 students. How this is calculated? (10+40+51+68+98) / Number of values. How many values I have? 10,40,51,68,98 - I have 5 Values. So,  (10+40+51+68+98) / 5 267 / 5 = 53. 4 Mode: It is the number that is repeating more times in the group of numbers. Example:  I have money in my Pocket. 1 - 500 rupees Note, 3 - 100 Rupees Note, 7 - 20 Rupees Note. Now, tell me which Note I have the Most? 20 Rupees Right? because I have 7 20 rupees Notes.  Exactly, that is how we check Mode. If you are given data with numbers (1,2,3,4,5,5,5,5,5,5,6,7,8,9) You know which is Mode. It is 5, because it is the most available number in this group. Median: It is the central Point of data.  You a...

As a Data Professional, Instead of showing data in a sentence or table, which is hard to read, You can show Data using suitable graph in Excel, Power BI, Tableau Etc. for better understanding  Column Chart Column Chart is made of Vertical Bars. Each Bar shows Each value.  Column Chart is mostly used to show the performance of an Employee every year, every month, etc... You can also use this chart to show Sales, Quantity, Improvement by time period. It works best if you have X axis = Timeline & Y axis = Quantity / Value. Bar Chart: Bar Chart is made of Horizontal Bars. Each Bar shows Value of Each Category. You can use this Chart to show Data by Category Like Products: TV, Mobile, Fridge. It helps analyze which is a Top Category and which is a Lowest Category. It works best if you have X axis = Value & Y axis = Category. Line Chart: It is used to show Trends over time. Internet Service provider Companies can check how the Internet speed in your area changes every Second...

 A Chart is a Visual Representation of Data Trends, Patterns and Insights.  Its like you are looking at a picture and understanding what is happening with the data. Same like watching a Movie instead of reading the Movie story. Why? Chart gives Fast, Better and Simple Understanding of a Big Complex Data. When you become a Data Analyst or Data Scientist in future. You will present your Data with Charts. Your Manager, Program Head, Clients, Directors.. they don't have time to read the entire data from a excel file or PowerPoint file.  A Chart will make it easier for them to understand the Situation, Progress, Profit, Loss, Improvement, Danger etc.. within few seconds of looking at the Charts. There are around 100 Charts available in Data Science World. Each has its own purpose. When you create Multiple Charts in a single page, it is called Report. When you build Multiple pages of report, it is called Dashboards.  If you create Best Quality & Easy to Understand Char...

Prediction - Finding out what will happen in Future. It may not be 100% Exact. But At least you know something is more likely to happen, with the help of prediction Analysis. This is called Predictive Analysis . One of the four important Types of Analysis. If you have last 10 months of students mark data, you can do predictive analysis and find future marks of the students. Why Predictive Analysis is Useful in Real Jobs? Sales Department : To Predict next month’s Profit, Sales, Product preference. Marketing Department : To Predict which customer is likely to buy a product. HR Department : To Predict which employee may leave the company in upcoming months. Education Sector : To Predict student performance and give early support before exams. Healthcare : To Predict patient risk level or future disease based on historic records. Government: To Predict Future Population Growth, Future Economy Level, Future Demands, Future Employment and business growth. Military: To Predict threats, Ear...

Artificial Intelligence means making Computers think like Human Brain, choosing correct & realistic decisions, answers based on the Current circumstance and importance. Personal Example: Data Science = What is Actually Happening in your Life. Machine Learning = What you are learning and experiencing in your Life. Artificial Intelligence = Taking Correct Decisions based on your Life Experience Another Example: You are AI Engineer & you created a Personal AI Friend using Python. Now, You give all information about your Financial Status, Economic Status, Emotional Status, Social Status, Current Situation in your Life, Current Situation in your Family, Current Situation in your Country etc etc... and your Current problems in an Excel file or SQL Database. Now you are giving this data to your AI tool which you created. 1. It will analyze the information, choose which is important and which is useless based on your current situation. 2. Now, it sends that important Information to Mac...

Data Science is the art of turning data into decisions by combining machine learning, software development, and traditional research to solve real-world problems. I know I know... But Explain Practically & Simply, So I know what Data Scientists DO!? I hear You! Look at this Image & Read the concepts in Data Science before you scroll further. Now: Lets Start with our School Memories.... Your Old school wants to find out which students are likely to fail in final exams , so they can give extra support early. But How can they find out? Of course, they can ask teachers. But teachers may have some favorite students, Some enemy students and some Own assumptions. Assuming who is better student and who is worst student randomly is a Risky Calculation. It cannot be always Correct. So, your School Needs a Data Scientist. Because Data Scientist Works with Data , Not with Assumptions. A Data Scientist who never even met the Students before, can make Right Calculations and Give Correct resu...

 Matrix என்பது வரிசை (Rows) மற்றும் நெடுவரிசை (Columns) கொண்ட ஒரு Table மாதிரியான Box. இதில் Numbers சேர்க்கப்பட்டிருக்கும். Row (வரிசை) என்றால் என்ன? Column (நெடுவரிசை) என்றால் என்ன? கீழே உள்ள Excel டேபிளைப் பாருங்கள்: நீங்கள் பார்க்கும் 1, 2, 3, 4, 5, 6, 7 — இவை எல்லாம் Row-கள் ஆகும். இவை Left to Right செல்லும். நீங்கள் பார்க்கும் Serial Number, Product, Quantity, Price, Sales -  இவை எல்லாம் Column-கள் (நெடுவரிசைகள்) ஆகும். இவை Top to Bottom செல்லும். இந்த முறை உங்கள் School Math Table, Excel Table, SQL Table மற்றும் பல Data தளங்களில் பயன்படுத்தப்படுகிறது. இது தான் Computer Dataகளை புரியவைக்கும் சரியான முறை. இதில் தரவை தேடுவதும், Filtering, Visualize பண்ணவும் எளிதாக இருக்கும். Row எப்படி வாசிப்பது? Row 1 – Serial Number, Product, Quantity, Price, Sales என்று இடம் இருந்து வலமாக வாசிக்க வேண்டும். Row 2 – 1, Product 1, 5, 25, 125 என்று வாசிக்க வேண்டும். Column எப்படி வாசிப்பது? Column A – Serial Number, 1, 2, 3, 4, 5 என்று மேலிருந்து கீழாக வாசிக்க வேண்டும். இந்த மாதிரி...

 A matrix is like a table or box with rows and columns that hold numbers. So, What is Row and What is Column? Lets take the below Excel table for Example: Look at the Table. You can see Number 1, 2, 3, 4, 5, 6, 7 - Those are all called Rows. You can see Serial Number, Product, Quantity, Price, Seles - Those are all Called Columns. This Method is used in your School Math Tables, Excel Table, SQL table and every other Table.. This is the Proper Method to store data, so a computer can understand the data and it will be easier to Search the data or Create a Visualization from the data. How you read the Row 1, You have to read as Serial Number, Product, Quantity, Price and Sales How you read the Row 2, You have to read as 1, Product 1, 5, 25, 125.  You will always read a Row from Left to Right. Now, How you will read the Column A, you have to read as Serial Number, 1, 2, 3, 4, 5 You will always read a Column from Top to Bottom. Now, the same way you will read this Matrix. This Abov...

 Linear Transformation என்பது ஒரு அளவை அல்லது அளவுகளின் குழுவை கணித விதிகளை பயன்படுத்தி மாற்றுவது. இதில் Relationship நேராக (linear) இருக்கும்.  இதன் அர்த்தம் என்ன? நீங்கள் ஒரு Input value எடுத்து அதற்கு ஒரு formula apply பண்ணி Output value உருவாக்குறீங்க. எளிமையான வார்த்தைகளில்: Scale பண்ணுறீங்க (அதாவது அளவை அதிகப்படுத்துறீங்க இல்ல குறைக்குறீங்க) இல்ல Shift பண்ணுறீங்க (அதாவது மேல, கீழ், இடம், வலது என நகர்த்துறீங்க) உதாரணங்கள்: ஒரு சம்பளம் ₹10,000 இருக்குது. அதுக்கு 10% அதிகரிப்பு கொடுக்குறீங்க → புதிய சம்பளம் = ₹11,000. இது Linear Transformation ஏனென்றால் நீங்க அளவை மட்டும் scale பண்ணுறீங்க. ஒரு மாணவர் மதிப்பெண்களுக்கு 5 bonus marks add பண்ணுறீங்க: Original Mark = 70 New Mark = 75 இது கூட Linear Transformation தான். ஒரு படத்தை Zoom பண்ணும் போது, structure அழியாமல் பெரியதா சின்னதா ஆகுது. இது Scaling ஆகும். Scaling என்பது Linear Transformation-ல் ஒன்றுதான். சுருக்கமாக சொன்னால்: Linear Transformation = Scale பண்ணுறது அல்லது Shift பண்ணுறது. ஆனால் உ...

 A Linear Transformation is a way to change a value or set of values using mathematical rules while keeping the relationship straight (linear), not curved or complex. It means taking some input values and applying a formula to get output values. In simple words: You scale (increase or decrease) or You shift (move up, down, left, right) the values. Examples: If salary is ₹10,000, and you apply a 10 percent increase → New Salary  = ₹11,000 This is linear transformation because you just scaled the value. If you add 5 bonus marks to student marks: Original Mark = 70 New Mark = 75 This is also linear transformation. Zooming an Image  without breaking the image structure   is scaling , which is one type of linear transformation .

 SCALAR:- In Data Science, most of the raw data we collect, store, and analyze are Scalar Quantities . 👉 These are measurements that have only value (magnitude) and no direction —which is what we usually need for business analysis, predictions, and decisions . Scalar Example:- ✅ Most commonly used Scalar Quantities in Data Science: Sales - $50,000 - It is a Simple Scalar Value Measuring the Money Profit - $30,000 - It is a Simple Scalar Value Measuring the Profit Cost - $25,000 - Scalar Value because it is only showing the Measurement of Currency Quantity Sold - 45 - Scalar Value Showing the Count of Products Sold Customer Age - 35 - Scalar Value showing the Count of Years since Customer is Born Income - Scalar value Etc., etc., As long as the values have only magnitude and no direction, they are scalar values . Why Scalar is Important in Data Science: Most business Key Performance Indicators (KPIs) are scalar values. All visualizations like bar charts, pie charts depend...

  Scalar is a measurement that has only value. Value means Magnitude, a Measure. But It has No Direction like Left, right, West, East etc.. It Simply has Value Only ✅ Examples: 🌡 Temperature → 30°C → Only magnitude, no direction. ⏰ Time → 5 hours → Only magnitude, no direction. ⚖ Mass (Weight) → 60 kg → Only magnitude, no direction. 🚗 Speed → 40 km/h → Only magnitude, no direction. Speed is just one example of a scalar quantity. Similarly, Temperature, Time, Mass, Length, Area, Volume,   all these are scalar quantities . If there is only magnitude (value) and no direction, it is called a Scalar Quantity . Vector is not just a value, it also has direction. Quantities that have both Magnitude + Direction are called Vector Quantities . ✅ Examples: ➡️ Velocity → 40 km/h North → Has both magnitude and direction. ➡️ Displacement → 5 km East → Has both magnitude and direction. ➡️ Force → 10 N Upward → Has both magnitude and direction. ➡️ Acceleration → 5...